Propose and implement autolink feature in wasm-ld

[kateinoigakukun]

I agree that the approach suggested by compnerd would be the simplest solution.
And I'm sure that we can make a new convention for the autolink in wasm tools conventions. (Yeah, but it requires a lot of effort)

So what should we do are:

1. Propose a new convention for autolink in Wasm object file conventions
2. Support llvm.dependent-libraries in Wasm target backend of LLVM to lower it in the proposed convention.
3. Support the new convention in wasm-ld
   If we accomplished them, we won't need this swift-autolink-extract workaround in Wasm target.

swiftlang#31912 (comment)